Chih-Ming Chen 
& Ding Cao
Numerous studies have confirmed that increasing vocabulary size is a critical part of learning English as a foreign language (EFL). The rapid development of mobile and game technologies has encouraged instructors to consider the potential of Mobile-Assisted Language Learning (MALL) with game. However, a mobile learning game that supports effective English vocabulary learning can only be designed after the effects of key design factors, including concentration, feedback, matching of the challenge to player skill, control, and immersion, on learning performance, have been examined. Therefore, this study assesses the effects of two different game-based English vocabulary learning apps with significantly different game design factors on learners’ performance, sustained attention, relaxation, and vocabulary retention. Analytical results reveal that learners who used the game with weak game design factors exhibited significantly better vocabulary learning performance, retention, and relaxation and significantly lower sustained attention level than those who used the game with strong game design factors. This study also verifies that gender differences existed between the two game-based English vocabulary learning apps with different game design factors. Girls achieved significantly better English vocabulary learning and retention in the game app with weak game design factors. Additionally, based on an interview with several research participants, “matching of the challenge to player skill” and “feedback” were the most important game design factors in game-based English vocabulary learning apps. DOI: 10.6575/JILA.202106_(98).0001
98-1